Re: [OT]Stupid question about sloped armour

On Wed, 1 May 2002, Roger Books wrote:

> 
> This has been bothering me for awhile.  How does sloped armour gain
> me anything?

It's just geometry, AFAIK, in two ways.

1. Rounds are more likely to bounce off upward, rather that 'stick'.

2. (the more important one) If you've got a round coming in parallel to
the ground, it's got to go thru MORE of an angled plate to reach the
squishy bits of the vehicle inside.

Say we have a 10cm sheet of armour - if it's perpendicular to the
round's
path, the round only has to go thru 10cm.

Tip the armour back a bit - or a lot - and your round has to go through
more actual thickness of armour on it's parallel-to-the-ground impact
path. Slope the armour back 45 degrees and your 10cm armour is
effectively
12-14cm thick or so, without adding anything to the weight of your
vehicle.

> 
> If I take the same mass of sloped armour and make armour perpendicular
> to the ground I gain the same thickness you would gain from the
> slope.  Space would remain the same (If I pivot the slope about
> the center everything I lose from the bottom reappears on the
> top.)

Nope, you're just reduced the *effective* thickness of your armour by
the
percentage (roughly) that it used to be sloped. Do a bit of scribbling
on
scrap paper, and you'll see what I mean. Draw two parallel lines for the
inner & outer surfaces of your hypothetical armour plate, and then
measure
lines passing thru at differing angles - non-perpendicular lines are
naturally going to be longer, equalling 'thicker' armour when it's
sloped.

> Where am I off? I'd think my reasoning would be obvious to
> any engineer.

I'm nothing even remotely resembling an engineer, and my math bites too,
but I think I've got the gist of it above.

Anyone who can give a better explanation - or correct me if I'm totally
off - please do!

Brian - yh728@victoria.tc.ca -
- http://wind.prohosting.com/~warbard/games.html -